SU718013A3 - Method of purifying (co)polymers of styrene from terminal monomer - Google Patents

Abstract

1535344 Purifying styrene polymers of residual monomer LABOFINA SA 21 Oct 1976 43757/76 Heading C3L Styrene polymers containing residual monomer are mixed with aromatic sulphonyl hydrazides and heated to 150‹ to 250‹ C. with kneading, which is above the decomposition temperature of the hydrazide, to lower the monomer content. The polymers are typically ABS, high impact polystyrene or SAN resins. The process is typically carried out in an extruder. Comparative procedures describe the use of other hydrazides.

Description

one

This invention relates to methods for the purification of styrene (co) polymers. The proposed method receive polymers of styrene with a significantly reduced content of residual monomers.

The copolymers containing styrene, in comparison with homopolymers of styrene, have better mechanical properties, less thermal deformation and better aging performance. The most commonly used copolymers containing styrene are SAN resins resulting from the copolymerization of styrene and acrylonitrile;

HTPS resins, which are prepared by polymerizing styrene in the presence of an elastomer, typically Polybutadiene rubber;

ABS resins, which are derived from styrene, acrylonitrile and elastomer.

These resins are prepared by conventional polymerization methods, i.e., bulk polymerization, suspension polymerization, or emulsion polymerization.

In industrial practice, however, a two-stage process is most commonly used, involving bulk polymerization at a temperature of about 75-125 ° C, followed by suspension polymerization at a temperature of about 75-150 ° C.

These styrene polymers are thermoplastic materials; they can be molded by any conventional method. They are used to make various containers for liquid and solid products.

However, when using any of the aforementioned methods of polymerization, residual monomer continues to be in the resin. In addition, it is technically impossible to make a complete polymerization to avoid the presence of residual monomer. For example, HIPS, SAN and ABS resins usually contain 0.1-0.5 wt.% Residual styrene monomer. If these resins are used as packaging materials for t1schevyh products, this content is too high.

A known method of purification of styrene (co) polymers from residual monomer by mixing styrene (co) polymers with Cj-Cij apcylaminosulfonic acid containing more than one SOjH group or amino group or alkali salt of this acid 11 However, the known method is very selective and not effective enough to remove residual monomer styrene.

The purpose of the invention is to increase the degree of occlucy;

In order to achieve the delivered Delhi in the proposed Method of purification of (co) polymers of styrene from residual monomer by mixing (co) polymers of styrene with sulfur-containing sulfur at Heating and stirring in X of the sulfur-containing compound, the iso-oh is -O-, -S-, -SN-or-GO-G-V-. or their mixtures and mixing are carried out at 150-250 ° C for 30-180 seconds. Sulfonic Idrazides are non-toxic, solid, odorless substances that are compatible with polymers. In addition, they are decomposed by heat and decomposition residues are non-toxic and usually eecupCTHiiiiyui. Sulfonylhydrazide and their residues do not exert any negative effect on the properties of styrene resins. Besides tggo, these aromatic sulfonic acid hydrazine are readily available products (unlike alkylsulfonylhydrazides). The amount of sulfonyl hydrazides used depends on the amount of residual monomers that were present before the treatment and whose presence is permissible in the treated resin. Thus, the amount of sulfo-hydrazide can be as low as 0.5 mol per I MOJib residue of the monomer present in the resin before treatment. Usually, the sulfonyl hydrazide is used in a co-efficient that corresponds to one; you eat with a metric110 metric amount per residual monomer. Although it is possible to use a processing agent in an amount greater than the stoichiometric use of the amounts, about two times

0.5-2 mol per 1 mol of residual monomer in the (co) polymer sulfonyl hydrazide of the general formula

H N

SOz-NH-NH2

 :

RI is hydrogen or an alkyl radical containing 1-4 carbon atoms;

RZ is -SOj-NH-NHHa when R is hydrogen or sulphonyl. hydrazide of the general formula

H N

X-ChS) bS02-mb-NH2 NN

H S02-NH-NH2 exceeding the stoichiometric, does not give any improvement in the results. The sulfonyl hydrazide is introduced into the styrene resin by displacing these components in a mixer or similar device. This process can be carried out in an extruder with a single or double screw. The treatment is performed at a temperature that depends on the decomposition temperature of the sulfonyl Schrazide used and which is, for example, for benzenesulfonyl hydrazide, 104 ° C for the pure product, for 1,3-benzenedisulfonylhydrazide, 163 ° C for the pure product, and 145 ° C for an industrial product, for -Thcsssulphonylsulfonylhydrazide, for 4,4-hydroxy-5g- (benzenesulfonylhydrazide 164 ° C for the crude product and for the industrial product, for 3,3-sulfo-bms- {benzenesulphonyl t-idrazide 15 3 -15 8 ° C. Usually the temperature in the extruder is 50– DOOS higher, h The decomposition temperature of the sulfonyl hydrazide used is: The residence time can vary from 30 to 180 seconds and is usually 60-150 seconds, and this time depends on the temperature in the extruder. It was found that the residual content of the X monomers in the resin treated by the proposed method significantly reduced, and that the treated resin can be used as a packaging material for foodstuffs Example 1. A HIPS resin containing 0.10 weight is placed in a single black extruder. residual styrene monomer, zinc stearate (0.06 wt.% by weight HIPS), lime (0.01 wt.% by weight HIPS) and di-777 g-butyl - “- cresol (0.14 wt.% by weight HIPS). The mixture was extruded at 220 ° C and with the residence time of the software c. After extrusion {ivania, the content of residual monomer in the HIPS resin is 0.08% by weight. The same experiment was repeated, but l-toluenesul (3 units of hydrazide (or about 1 mole of hydrazide per 1 mole of residual monomer) was added to the mixture before extruding ... -, I After extrusion in a similar manner Monomer 0.03 wt.% Table 1 shows the characteristics of the polymer obtained, from which it is clear that using a sulfonyl hydrazide does not adversely affect the mechanical properties of the resin, and resin A is a HIPS that was extruded without toluene processing fonilgidrazidom and the resin B is HIPSi which was ekstrudirova after obrabrt sulfonilgidrazydom ki Table 1 Impact resistance Izod UE e aging kg / cm flow index at 200 ° C, r / JO min.:

NgK-sh-zog

HgN-NH-SOz HZN-NH-S02 QVsoz-NH-M W, SOj-m-NH2HiN: i3, iv

SOz-NH-NH2 (A),

Claims (3)

S02-NH-NH2 (B), Continued haPl.1 Polymer Indicators Proc. 1Gryn, Modulus of stretch, 21.280 20.650 Elongation,% 43.447 2625 Bending Impact resistance at 41.5 41.5 load drop kg “cm Example 2. The test described in example 1 is repeated with a mixture of HIPS containing 0.12% by weight of residual monomer, zinc stearate (0.06% by weight), lime (0.01% by weight) and di-greg-bugal- and-craBola (0.14 wt.%). The extruder is heated to 160 ° C and the dwell time is 150 s. After treatment, the resin contains 0.04 wt. 7o residual monomer. For comparison, other hydrazides were used instead of benzenesulfonic hydrazide. The following amounts of residual styrene were obtained after treatment, wt.%: J and Toluene hydrazide 0.10 g Glutaric hydrazide 0.10 Salicylic hydrazide 0.11 These tests show that hydrazides that are not sulfonyl hydrazides are not active, the residual styrene content is practically does not decrease. Example 3. HIPS resin containing 0.10 wt.% Residual styrene monomer is displaced with stearate (0.06 wt.%), Lime (0.0 wt.%), Di-greg-butyl-p-cresol (0 , 14 wt.%) And one of the following cplJonOnHydrazides: S02-NH-NH2 W), HN-OzS SOj-KH-m "These sulfonyl hydrazides are used in an amount corresponding to 1.5 times the stoichiometric amount calculated on the amount of residual styrene monomer in HIPS resin. The operating conditions and the results obtained are summarized in the table below. 2. Table 2 Example 4. A SAN resin containing 0.14% by weight of residual styrene and 0.08% by weight of residual acrylonitrile, hdank stearate (0.07% by weight of SAN resin) is placed in an extruder with a single black in a clod. ) and and-toluensulfonylhydrazide (0.4 wt.% by weight of the resin SAN). After extrusion at 220 ° C and residence times of about NO, with a residual styrene content of 0.05% by weight and content. residual acrylonitrile 0.02 wt.%. For comparison, the same procedure was repeated, but without the addition of p-toluenesulfonyl hydride; After extrusion, the monomer content is 0.12 wt. (for styrene) and 0.07 wt.% (for acrylonitrile). ; Example 5. In: an extruder with a single worm placed an ABS resin containing 0.5% by weight of residual styrene and 0.2% by weight of residual acrylonitrile, buccal stearate (0.07% by weight of ABS resin), di- tri-buTTiui-n-cresol (0.1 wt.% by weight of ABS resin) and p-toluenesulfonyl hydrazide (0.1 wt.% by weight of ABS resin). After extrusion at 200 ° C and with a residence time of 110 with a residual monomer content of 0.06% by weight, respectively (for styrene) and 0.03% by weight (for acrylonitrile). Example 6. (for compare). HIPS with a content of 0.10 wt.% Residual styrene monomer, zinc stearate (0.06 wt.% By weight HIPS), lime (0.01 wt.% By weight HIPS), dn-greg are added to a simple screw extruder. -butyl-p-cr, ash (0.14 wt.% by weight of HIPS) and 2-ethylaminosulfonic acid (0.14 wt.% by weight of HIPS). 7 8 The extruder is heated to 160 ° C and held for 150 s. After treatment, the resin will gain 0.09% by weight of the residual staol monomer. This example clearly shows that the alkylaminosulfonic acid Cr-Cc, when removing monomers, acts very selectively and does not sufficiently effectively remove the residual styrene monomer. PRI me R 7. HIPS is introduced into a simple screw extruder with a residual styrene monomer content of 0.10 wt.%, Zinc cteapaT (0.06 wt.% By weight of HIPS), lime (0.01 wt.% Of HIPS weight), di-greg-bztil-Cresol (0.14 wt.% by weight HIPS) and n-toluenes Lfonyl hydrazide (0.4 wt.% by weight HiPS). The molar ratio of the sulfonyl hydrazide and styrene monomer is 2, 2. The mixture is in an extruder at 180 ° C for software with. After extrusion, the residual monomer content is 0.03 wt.%. L p i m e r. 8. In a simple screw extruder, the same mixture as described in Example 1 is introduced, but p-toluenesulfonyl hydrazide is used in an amount of 0.1% by weight;%. The molar ratio of sulfonyl hydrazide and styrene monomer is 0.5. The mixture is in an extruder at 220 ° C for software with. After extrusion, the residual styrene monomer content is 0.06 wt.%. Example 9. A simple screw extruder is injected with HIPS with a residual monomer content of styrene of 0.12% by weight, stearate Ts11nka, 06% by weight of HIPS), lime (0.01 wt.% By weight of HIPS), di-greg -butyl-l-cresol (0.14 wt.% based on the weight of the HIPS) and -toluenesulfonylpdrazide (0.2 wt.% of the weight of the HIPS). The mixture is in an extruder at 150 ° C for 150 seconds. After extrusion, the residual styrene monomer content is 0.05% by weight. Example 10. The same mixture as described in example is introduced into a simple screw extruder. 3. The mixture is kept in. extruder at 250 ° C for 90 s. After extrusion, the residual styrene monomer content is 0.05% by weight. Thus, the proposed method can effectively (co) polymer styrene from the residual monomer. Claims The method of purifying styrene (co) polymers from residual monomer by mixing styrene (co) polymers with a sulfur-containing mediation during heating and stirring, characterized in that, in order to increase the degree of purification, 0.5-2 mol per mole of sulfur-containing compound is used. I mol 9 of residual monomer in (co) full nylhydrazide of the general formula H H KI SO -HH-NH2 HzN-HN-OzS. H2K-nn-OgH = X where X is -O-, -S-, -CHj or -SOj-, or their mixtures and mixing is carried out at 150-250 ° C for 30-180 s. sulfo-where RI is water or alknl (-X-ObS02-NH-NH2 H HH H 718013: 10th radical, containing 1-4 atoms, carbon; RJ is the radical -SOj-NH-NHj, when R , is hydrogen, or a sulfonyl hydrazide of the general formula H HH H H H H H H $ 0g-k-kn Sources of information taken into account in examination 1. Japan patent ((50-23419, cl. 25 (1) C 141.1 , published in 1975 (prototype).